Method for obtaining powder from highly concentrated high viscous solutions

Abstract

The present invention relates to a method for obtaining a purified solid powder from highly concentrated, semi-liquid, high viscous solutions containing one or more solutes and a first solvent. The method comprises contacting the highly concentrated solution with a second solvent under high shear mixing, wherein the second solvent is miscible with the first solvent and wherein the solute has very low solubility or no solubility at all in the second solvent. Thereby a suspension of purified fine particles is obtained which can be easily separated to obtain a fine powder of the solute.

Description

1. Field of the InventionThe present invention relates to a method for recovering dry solid powder from highly concentrated, high viscous solutions.2. Discussion of the Related ArtDifficulties in recovering dry solid particles from highly concentrated, high viscous, semi-liquids solutions are known in the art. In particular, such difficulties arise when the solids present in the solution constitute a mixture and not a pure substance, as often occurs in the processing of substances from natural sources. In situations like that, the solute does not crystallize easily, preventing simple separation. For example, it is well known that solutions of sugar mixtures (i.e., molasses) and especially those which contain oligosaccharaides, are very difficult to crystallize. Recovery of the solids by means of solvent evaporation also fails many times to give pure and fine solid particles, since small amounts of liquid are entrapped between the amorphous solid skeleton. Thus, evaporation often res...

AI Technical Summary

Benefits of technology

"The present invention provides an economical method for obtaining purified solid substances from highly concentrated viscous solutions containing solutes and solvents. The method involves subjecting the solution to high shear mixing with a second solvent that is miscible with the first solvent. The second solvent is added while subjecting the solution to high shear mixing, resulting in a suspension of fine particles in a liquid phase consisting of the first and second solvents. The solids can then be easily separated by filtration. This method is simple, does not require complicated equipment, and the solids are obtained as dry, non-sticky pure powder that does not adhere to equipment walls and does not cause clogging problems. The method is particularly useful for de-oiling commercial lecithin powder."

Problems solved by technology

In particular, such difficulties arise when the solids present in the solution constitute a mixture and not a pure substance, as often occurs in the processing of substances from natural sources.

In situations like that, the solute does not crystallize easily, preventing simple separation.

For example, it is well known that solutions of sugar mixtures (i.e., molasses) and especially those which contain oligosaccharaides, are very difficult to crystallize.

Recovery of the solids by means of solvent evaporation also fails many times to give pure and fine solid particles, since small amounts of liquid are entrapped between the amorphous solid skeleton.

Thus, evaporation often results either in a dough-like substance which cannot be dried further or in one lump of hard solid which is difficult to handle and needs to be further pulverized.

Furthermore, soluble contamination remains entrapped in the dried solid so obtained.

Moreover, complete evaporation often requires high temperatures which might destroy the substances to be recovered.

Powders have prolonged shelf life, are easier to handle and to pack and consequently are cheaper to transport, while liquids, having higher volume and weight, impose packaging and leakage problems.

In particular, when relating to food additives, syrup-like additives are limited to "wet-foods" and cannot be used for powdered foodstuff.

However, these methods require sophisticated and expensive equipment, are high energy consuming or need large solvent quantities, and the results are not always satisfactory.

No further purification is achieved by the drying methods and in many cases, the particles formed tend to stick onto the equipment walls and to clog equipment passages, making the process cumbersome and time consuming.

Moreover, in order to spray dry or freeze dry, the concentrated solutions need to be diluted to a much lower concentration, thus these processes are energy consuming as well.